Anion-incorporating

It was found that utilization of QAS with increased steric accessibility of exchange center, containing nitrogen atom with three methyl substituents and one super lipophilic substituent, - tris(2,3,4-dodecyloxy)benzyl, - leads to dramatic, up to 7 orders, increase of ISE s selectivity towards sulfate in the presence of single-charged anions. Incorporation of hexyl 4-trifluoro-acetylbenzoate into membrane leads to additional substantial increase - up to 4 orders - in sulfate selectivity. 

Nonstoichiometry of the oxides can be due to a number of reasons, such as hydration,159 incomplete oxidation,158 and the generation of defects at interfaces.157 An important factor affecting the chemical composition of the oxides is the incorporation of electrolyte species into the growing alumina. There have even been suggestions to use this for impurity doping of oxides and modifying their properties.161 Various kinds of anion distributions and mechanisms of anion incorporation and their influence on oxide properties have been reported. The problems attracting attention are ... 

What are the kinetics of anion incorporation into the growing oxide and how is this process influenced by anodization conditions ... 

Does anion incorporation influence the oxide formation, and what is the mechanism of anion pickup ... 

Data on Anion incorporation into Anodic Alumina... 

Kinetics of Anion Incorporation into Growing Alumina Films... 

Data on anion incorporation into a growing porous oxide were obtained Fukuda and Fukushima.165,166 Their study was the first to demonstrate a correlation between the kinetics of accumulation of oxalate165 or sulfate166 anions and the change of porous oxide growth stages. The results of galvanostatic and potentiostatic... 

When the results for oxide growth and anion incorporation172,160 are compared with the kinetics of space charge accumulation in barrier and porous alumina films [see Section IV(1)], it can be concluded that anion incorporation modifies the electrostatics of the external oxide interface, thus influencing oxide dissolution and pore formation.172... 

Photoluminescence (PL) of anodic aluminum oxides was first investigated in films formed in organic acids, the most intense PL being in those formed in oxalic acid. Tajima, in his comprehensive review315 on electro- and photoluminescence in anodic oxide films, concluded that PL centers are carboxylate anions incorporated into the oxide. On the other hand, Eidel berg and Tseitina316 proposed... 

The appearance of oxidation peaks in the CV is a direct evidence of PF f and BF 7 anions incorporation within the SWNT structure. The macromolecule Cn should then bear a positive charge as a result of subsequent oxidation following. In the case of PF 7 the anodic oxidation is ... 

Fig. 10 (a) Structure of the mixed valence compound [Cun(hfac)2(TTF—CH=CH—py)2] (PF6) -2CH2C12, showing alternating organic/inorganic layers with the PF6 anions incorporated in the TTF layer, (b) Projection in the ab plane showing the separation of the TTF dimers by the PFfi- anions... 

Further six-co-ordinate anions incorporating an a-hydroxy-acid residue, e.g, (114), have been prepared, and the use of salicylic acid has given the anion (115), containing... 

Using coprecipitation methods with a suitable mixture of solutions described above, the resulting LDH materials are often poorly crystallized and exhibit compositional fluctuations due mainly to the difference in the values of the pH at which the precipitation of M(II)(OH)2 and M(III)(OH)3 hydroxides occurs. Consequently, the chemical formula of the final material may not reflect the composition of the solution prior to the precipitation as noted in Chapter 1. Controlling the amount of anion incorporated under such conditions is very difficult. A "chimie douce method has been proposed by Delmas et al. in an effort to overcome this problem [181,182]. The process is illustrated schematically in Fig. 8. Since the synthesis starts from a highly crystalline layered y-oxyhydroxide precursor, it was suggested that this favored the formation of very crystalline LDHs with controllable M(1I)/M(III)... 

The homopolyatomlc or Zlntl anions Incorporating post-transitions elements of groups IV and V which have been so synthesized and structurally characterized are listed In Table I, together with their observed symmetries and other ions or molecules with which they are Isoelectronlc. As a matter of fact only three of those given, Sng ", Sb " and were observed... 

The reactions with H2S of complex metal anions incorporated into LB films made from DDAB have also been studied (10). The stoichiometry of the reaction can be represented as given in Eq. (5) ... 

The ligand contributes a bridging alkoxide and the metal coordination sphere is completed with one bridging and two terminal chloride anions. Incorporation of a carboxylate moiety in the system resulted in new compounds,... 

Palladium catalyzed cyclization of l-iodo-2-((propa-l,2-dienyloxy)methyl)benzene 150 occurs with concomitant anion incorporation to furnish 4-substituted-l//-isochromenes 151 (Scheme 49) <1998TL435, 2000J(P1)3799>. In the presence of norbornadiene 152, the initially formed azide can undergo a further 1,3-dipolar cycloaddition reaction and fragmentation to give l-((l//-isochromen-4-yl)methyl)-l//-l,2,3-triazole 153 (Scheme 49) <1998TL435, 2001T7729>. 

Figure 38 Structure of the [Mo3S7(mba)3]2 anion incorporating the mba2 anion of 2-mercaptobenzoic...

It has been shown that the concentration of counterion employed not only has an effect on the amount of anion incorporated into the polymer but also on its structure... 

As the polymer is reduced, anions are no longer electrostatically attracted and can leave the polymer however, if this process is too slow, then charge compensation may be achieved by cation incorporation, the cation coming from the electrolyte in which the polymer is reduced. In some cases, where the anion incorporated during the synthesis is bulky (e.g., a polyelectrolyte such as polyvinyl sulfonate) and/or has a bulky hydrophobic component (e.g., a surfactant molecule such as dodecyl sulfate), the cation incorporation process will predominate and the polymer mass will increase upon reduction (see Chapter 1). The change in resistance, at least in solution as measured here, is much less when cation rather than anion movement predominates in the polymer oxidation/reduction process. 

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